Transmission Control Systems: Description and Operation

The AW-4 is a 4-speed, electronically controlled automatic transmission.

Running gear consists of an oil pump, planetary gear sets, clutch and brake units, hydraulic accumulators, a valve body with electrical solenoids and a Transmission Control Module (TCM). Cables are used for shift and throttle pressure control. A park/neutral position switch permits engine starting in Park and Neutral range only.

The valve body solenoids are controlled by signals from the TCM. Signal sequence is determined by vehicle speed and throttle position.